Power Supply Functions - Siemens A55 Repair Documentation

Pin
Mode
Requirements
Trickle charge VDD_CHARGE
mode to be able EXT_PWR
to support
charging of the
battery
6.1.3

Power Supply Functions:

Functions Pin
Requirements
Switching on the ON_OFF,
mobile phone ON_OFF2,
VDD_CHARGE
V1.20
A55/C55_Hitachi
Description
In case of a rising edge at
(PinC3) the
interim mode. In this mode, the oscillator and
the reference are started. The fuses are read
in. If the voltage is high enough (after a delay
time of 1 ms to filter a ringing), the internal
signal EXT_PWR
up continues. The
is below threshold. In Trickle Charge Mode,
first the charge unit starts and charges the
battery in case of under voltage. After reaching
this threshold voltage or if the battery has
enough voltage from the beginning, a start up
similar to the regular startup mode is initiated.
In case of voltage drop under battery threshold,
the first trickle charging can be started again
until the Active Mode is entered. In this case,
the internal VDDREF regulator, the reference
generator and oscillator are started and the
ASIC is supplied by VDDREF. If any failure is
detected, the
Sequence
There are 3 different possibilities to switch on
the phone by external pins:
- VDD_CHARGE
after POR or high level at end of POR
signal
- ON/OFF
- ON/OFF2
In order to guarantee a defined start-up
behavior of the external components, a
sequential power up is used and the
correct start up of these blocks is
supervised. In active mode, a continuous
signal at watchdog is needed to keep the
system running. If the signals fails, the
ASIC will switch to power down mode. It
must be guaranteed that each start-up
condition does not interfere and block the
other possible startup signals. In case of
failure during start-up, the device will go
back to power down mode. To guarantee
that VDDCHARGE
sensed we must be able to detect whether
the VDDCHARGE
rising edge during POR (this can happen in
case of an empty battery). Therefore this
signal is sensed as level sensitive at the
end of POR and edge sensitive after POR
signal.
Page 29 of 48
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VDD_CHARGE
ASIC goes from power down to
is going to H and the power
ASIC shuts off if the voltage
ASIC is switched off.
(PinC3) with rising edge
(PinH2) with falling edge
(PinJ3) with rising edge
(PinC3) is always
(PinC3) will have a
ICM MP CCQ GRM
04/03